Has anyone ever experienced any issues with installing Centos on an HP Z800?

I have installed CentOS 7.6 from the ISO release on two separate HP Z800 machines, and neither one of them will perform a proper shutdown or reboot. They just hang at either "Powering Down" or "Rebooting", and eventually have to be powered down with the power switch. They both showed this problem right from the initial reboot performed by the installation program.

Both Z800 systems have been flashed with the latest BIOS from HP.

I am not sure it is related or not, but the command "sudo lshw" hangs at the USB stage on both systems. The command "sudo lshw -disable USB" will run OK on both systems.

As a test, I tried Unbuntu 18.04.1 on one of them, and it shutdown and rebooted fine. I would however prefer to stick with CentOS.

Any thoughts on how to systematically trace this shutdown issue would be greatly appreciated. I am a newbie, and am not real familiar with the various diagnostic resources available under CentOS.

I realize it's nearly 18 months since you post. It popped up on Google near the top of the results for an unrelated search.

As I have some experience with this, I believe the answer is in the ACPI settings for the kernel. You might try to boot the system with the noacpi option on the kernel command line, and see if anything changes during the shutdown.

You might also try switching to the command line mode (Ctrl+Alt+F1) and using the shutdown command (systemctl reboot) to observe the shutdown process in detail and identify anything that is hanging it up such as a running service that won't stop for some reason or disks not umounting, etc.